Fibre cement lining board and uses thereof

ABSTRACT

The present invention relates in a first part to a fibre cement lining board for use as a replacement to building wrap which can be used to form a sub wall on the outer surface of a wall frame, and to building wall structures and methods of constructing buildings using these particular lining boards. The invention also relates to a new method of constructing framed dual skin walls using the lining boards, particularly brick or masonry veneer walls, and to the wall structures formed by that method.

FIELD OF THE INVENTION

The present invention relates in a first part to a fibre cement liningboard for use as a replacement to building wrap which can be used toform a sub wall or inner skin on the outer surface of a wall frame, andto building wall structures and methods of constructing buildings usingthese particular lining boards. The invention also relates to a newmethod of constructing framed dual skin walls using the lining boards,particularly brick or masonry veneer walls and to the dual skin wallstructures formed by that method.

The inventions have been developed primarily for use in the domesticbuilding field and will be described hereafter in reference to suchapplications. However, it will be appreciated that the inventions couldreadily be adapted for use in commercial building construction ifrequired.

BACKGROUND OF THE INVENTION

One major limitation impacting on construction costs and totalconstruction times, particularly in the domestic dwelling market inAustralia and New Zealand, is the general need with all conventionalmethods of dual skin framed building construction, that is framestructure plus separate veneer or cladding, to fully complete theexternal envelope of a building to a stage referred to generally as“lock up”, prior to commencing the internal lining work and fit out.

For example, with a typical brick veneer structure, once the foundationslab or blockwork is complete, the wall, floor and roofing frames willfirst be erected. This may include the step of applying structuralbracing sheets, if the frame structure requires strengthening of thisform. The wall and the roof frames will typically then be covered in anappropriate moisture management barrier in the form of paper or foilbuilding wrap or sarking membrane prior to erecting the external brickwall and applying the selected roof covering. As these membranematerials are not particularly wind tolerant, they are generally onlyapplied just prior to the outer brick work being erected and immediatelyprior to the roofing battens being applied to the roofing frame.

In some instances, the final roofing material, be it tile or metalroofing sheets and the like, are not installed until the outer brickwork skin has been fully erected. Depending on the availability of thebrick layers and other relevant tradesmen, it is not unusual to seebuilding frames exposed to the elements for fairly long periods, whichcan result in deterioration of the structural frame. Even where the roofis installed shortly after the building frames are erected, there canstill be significant delays before the protective outer brick wall isfinished and “lock up” can then be achieved.

Similar comments apply in relation to most of the more commonly useddomestic dwelling construction techniques for framed structures thattraditionally use weather resistant membranes which are finished with anouter panelized or plank formed cladding material.

It is object of the present invention to provide one or more buildingsolutions that overcome or ameliorate the above discussed disadvantages,or which at least offer a useful alternative.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided an outerframe lining board in the form of a fibre cement sheet having athickness of more than 3 mm but less than 4 mm, which sheet ispre-sealed on at least one major face prior to installation.

In one preferred form the thickness of the lining board is around 3.5mm.

Advantageously, it has been found that a fibre cement sheet of thisthickness offers a cost competitive alternative to building membraneswhich is still easy to handle, yet strong enough to also provide aweather barrier and security barrier sufficient to achieve “lock up”.

Preferably the fibre cement sheet forming the lining board is configuredby method of manufacture, composition, structure or treatment, or anyone or combination of these, to meet the local applicable standards inrespect of at least air and moisture barriers. In other embodiments thefibre cement sheet may also be configured to meet other standardsrequirements in relation to bracing characteristics as would apply torigid sheathing.

In one preferred form the outer frame lining board includes integrallyformed markings to assist with alignment of fasteners with standard studspacings and the like and/or to facilitate easy and accurate cutting andsizing of the sheets. This marking may be in the form of a grid patternthat is printed on or formed in the surface of the board.

Ideally, the board is also marked to distinguish the lining board as aproduct originating from the applicant or one of its subsidiaries. Inone form the board is distinguished at least in part by use of a coloredsealant that preferably results in a wash of a green hue.

According to a second aspect of the invention there is provided a methodof construction of a framed dual skin wall structure including the stepsof:

erecting an internal structural wall frame in situ;

applying a plurality of fibre cement lining boards which are pre-sealedon at least one major face prior to installation to fully cover and sealthe outside of the wall frame excluding window and door openings andother designed penetrations to form a first inner wall skin,

applying a sealed roof or roof cover; and

closing off the designed penetrations to achieve a sufficiently sealedbuilding envelope to achieve “lock up” prior to subsequentlyconstructing a second outer wall skin in the form of an external blockwall or external cladding.

Preferably, the fibre cement lining board has a thickness of more than 3mm and less than 4 mm.

In one form the framed wall structure is a brick or block style masonryveneer structure. In other forms the framed wall structure relates towalls having some form of panelised or plank style outer cladding.

According to a third aspect of the invention there is provided a framedwall structure made in accordance with the method of the second aspectof the invention.

Preferably, the method of the second aspect of the invention and/or thewall structure of the third aspect of the invention uses the liningboards of the first aspect of the invention.

DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is a cut-away perspective view showing part of a brick veneerwall structure in accordance with a third aspect of the invention,incorporating the preferred outer frame lining board in accordance withthe first aspect of the invention.

FIG. 2 is a cut-away perspective view showing part of a plank clad wallstructure in accordance with a third aspect of the invention,incorporating the preferred outer frame lining board in accordance withthe first aspect of the invention.

FIG. 3 is a perspective cut-away view showing a typical outer framelining board layout as applied to a timber frame.

FIG. 4 illustrates a typical lining board vertical on-stud jointingarrangement on a timber frame.

FIG. 5 shows a typical lining board vertical off-stud jointingarrangement on a timber frame.

FIG. 6 shows a typical lining board horizontal joint with flashingarrangement on a timber frame.

FIG. 7 shows a typical lining of the board external corner jointarrangement on a timber frame.

FIG. 8 shows a typical lining of the board internal corner jointarrangement on a timber frame.

FIG. 9 is a perspective part view illustrating an outer frame boardexternal corner to horizontal joint arrangement.

FIG. 10 is a perspective part view illustrating a typical pipepenetration through the outer frame lining board.

FIG. 11 illustrates preferred flashing tape arrangements around window,door, meter box and other penetrations.

FIG. 12 is perspective part view illustrating a typical apron flashingarrangement.

FIG. 13 is a perspective view illustrating a typical flashingarrangement at a junction between a balustrade and a wall.

FIGS. 14 and 15 are each cross-sectional views of the lining board,frame and foundation detail.

PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIG. 1, there is shown a perspective cut-away view of partof the brick veneer wall structure 1 according to the invention. Thewall structure incorporates an outer frame sub wall 2 formed from aseries of lining boards 3 secured to the structural frame 4.

In the preferred form, the outer frame lining board 3 comprises a fibrecement sheet having a typical thickness of between 3 and 4 mm, which inthe preferred form is around 3.5 mm, and which is sealed on at least onemajor face 5. The fibre cement sheet consists essentially of cement or acalcium silicate formed by the chemical reaction of siliceous and acalcareous material, reinforced by fibres. Process aids, fillers, andpigments which are compatible with fibre-reinforced cement may be added.The exact composition, method of manufacture and/or method of treatmentor coating of the fibre cement sheet will be selected to meet therequisite performance characteristics of the final lining board.

In the preferred form, it has been found, quite surprisingly that a 3.5mm thick cellulose fibre reinforced cement sheet coated on the outerface and all edges with a Siloxane Sealer, which reacts with the FibreCement board to form a Silicone resin seal on the surface of the sheet,results in a lining board which is easily handled and relativelyinexpensive. It also readily meets with various New Zealand standardsrelating to both sheathing boards and to rigid air barriers, such asAS/NZS 2908, and the provisions of the New Zealand Building Code ClauseE2 External Moisture (including the requirements of Table 23 of E2-AS1)and is suitable for use in very high wind speed zones as specified inNZS 3604. In this regard the preferred lining board of the applicant hasbeen tested to comply with the performance requirements of the NewZealand Building Code (NZBC) and has been BRANZ appraised.

In a preferred form, the lining board 3 also includes various markingson the sealed surface 6 to assist with alignment and spacing offasteners with standard stud spacings etc and/or to facilitate easy andaccurate cutting and sizing of the boards. The markings may be printedon or formed into the surface of the board. In one form the pattern maybe in a grid form such as that shown in the drawings, which includesvertically extending grooves that can also assist in the drainage ofmoisture from the outer sealed surface of the board.

Ideally, the board is also marked to distinguish the lining board as aproduct originating from the applicant or one of its subsidiaries. Inthe preferred form the board is distinguished at least in part by use ofa colored sealant. In the preferred form the colour tint provides a washof a green hue across at least a portion of the board surface. A tintproviding standard colour readings on an L*a*b scale of DL-0.33; Da−0.46, Db 0.18 would provide a suitable green hue.

Turning next to FIG. 2, there is shown a cut-away perspective part viewof an alternative clad wall structure 7 that also uses the preferredlining boards 3 of the invention, to which an exterior cladding in theform of weather board planking 8 is applied. While FIG. 2 shows astructure whereby the cladding is secured directly over the liningboards, in other structures battens (not shown) are first applied overthe lining boards and the cladding is secured to the battens. Similarly,the cladding may be in other forms such as panellised cladding ratherthan the planking that is shown. Regardless, it will be appreciated thatthe installation process for securing the lining boards 3 to theunderlying structural wall frame 3 is substantially the same for alldual skin wall structures and this procedure is described in more detailhere after.

However, prior to describing detailed installation procedures, it isworth providing an overview of the lining boards and systems/methods ofthe inventions. In this regard, the advantages of the lining boards andsystems of the invention are numerous. Firstly, the lining boards, whenappropriately installed, eliminate the need to apply any form ofbuilding wrap. Furthermore, they can in many instances alsosimultaneously remove the need for structural bracing boards or,alternatively, be used solely as a highly durable but relatively lowcost bracing boards. Whilst rigid air barriers have been used incommercial buildings systems, these have all been too heavy andexpensive for use in the domestic market, particularly when compared tothe cost of using building wrap. The fact that such a thin fibre cementbased lining sheet can be so versatile in terms of function andstructural capabilities, as well as handlability, has been surprising.Also, as alluded to above, the new lining board also readily facilitatesa radical change to local domestic dual wall framed buildingconstruction methods that can significantly reduce total constructiontimes and associated costs. It can also reduce the number of siteinspections required during the construction process.

In this regard, the new lining board enables a builder to erect a costeffective sub-wall directly on to the frame which, in combination withthe installation of doors, windows, penetration covers and appropriateflooring and/or roofing, is capable of fully protecting the outsideenvelope of a dwelling. This means that a building can reach aneffective “lock-up” stage early in the construction process, so thatwork on the interior can commence before the outer wall, be it claddingor brick etc, is even started. This also means that a single buildinginspection can be booked for both final internal and external sign off.In New Zealand, the product and method of the invention proposed forlaunch has been appraised by the relevant authorities and approved toallow exposure of the installed lining sheets to external elements for90 days. This means that delays in installation of the final outer wallstructure will not in turn delay interior fit out work. In addition theproduct is resistant to fire and damage from moisture, particularly wheninstalled as prescribed. It is also rated for very high wind speedzones.

What is important in the construction method of the invention is thatthe lining board meets the relevant air barrier standards and isinstalled in a manner whereby the building envelope around the frame isappropriately sealed and secured. To this end each of the panels must beadequately sealed at adjacent edges and at boundaries with various wallopenings and penetrations.

While there may be a number of ways in which this can be achieved,preferred methods of installing the lining panels 3 will now bedescribed with reference to FIGS. 3 to 16.

Firstly, a structural wall frame 4 must be provided in accordance withthe relevant local standards or comply with a specific engineeringdesign requirements. For example, for the New Zealand market for whichthe products and systems have originally been designed, the stud spacingand nogs spacing must not exceed 600 mm centres and 1200 mm centresrespectively. A minimum of 45 mm wide stud is required at the liningboard vertical joints for jointing on stud. The framing will of coursealso need to be suitable for installing the selected exterior claddingin the event that a cladding material is to form the final outer wallskin.

The lining boards 3 will then need to be selected and, if required, cutto fit the wall or fit around a wall opening. In the preferred form, thelining boards have a grid formed into the surface of the boards whichmakes it easier to accurately cut the boards using a score and snapknife. It is important that the lining boards be fitted with the sealedgrid marked surface facing away from the frame 4. Fixing and sealingthen follows as described below.

FIG. 3 shows the general board to frame layout with the numbered arrowsindicating the Figure reference where various features are shown in moredetail. Where the lining board is intended for use as a general rigidair barrier to replace flexible building wrap material, there is anoption to form vertical joints on or off the stud and methods for doingthis will be described hereafter. However, where the product is used toachieve structural bracing, or edges of the lining board must besupported and fixed to the framing. In this regard, any vertical jointsmust be formed on the studs ideally with a gap of 1-2 mm maximum betweenthe lining boards.

As indicated above, there are two options for vertical jointing of thelining board in general applications, on stud jointing and off studjointing.

The on stud jointing is achieved by forming the joint on a stud 10 asshown in FIG. 4. As indicated a gap 11 is provided between the twolining boards 3 and the lining boards are preferably nailed to the studwith nails 12 as shown. A tape 13 is then applied to cover the nails 12and gap 11 along the full length of the board edges.

Off stud jointing is preferably achieved by using a uPVC jointer 15 toform the lining board vertical joint away from the stud as shown in FIG.5. The jointer 15 is then fixed to the bottom and top plates and to thenogs/dwangs.

Horizontal joints may be flashed using a uPVC horizontal flashing 16 ofthe kind shown in FIG. 6. Typically, a minimum gap of 15 mm is left atthe floor joist or is specified by the project engineer. When jointingin the middle of a floor height, a 10 mm minimum gap is usuallyrecommended. In this regard, the horizontal edges of the lining board 3should not be fixed into the solid timber floor joists 17. The flashingshould ideally be lapped by 35 mm minimum on both sides of the joint asshown in the drawings.

Internal and external corner joints can be sealed using a 75 mm widesealing tape as shown in FIGS. 7 and 8. Furthermore, when using uPVChorizontal flashing 16, the internal and external corner flushing jointsmust also be sealed using a 75 mm minimum width joint sealing tape 18 asshown in FIG. 9. All penetrations such as pipe penetrations through theinstalled lining boards 3 must also be properly sealed using a flexibleflashing tape or sheet 19 as shown in FIG. 10. Ideally, a 100 mm minimumcover flashing is maintained over the lining board 3 around thepenetration with a minimum of 25 mm of flashing tape 19 extending overthe pipe 20.

To achieve an adequate seal at the junction with a soffit, the liningboard ideally needs to extend up to the top of the top plate or go pastthe top plate.

In order to provide full weatherproof sealing to the finished buildingenvelope, it is important that exposed timber framing around the window,door, meter box and other penetrations be covered with a suitableflashing such as a 100 mm wide flashing or sealing tape 21 as shown inFIG. 11. Furthermore, the flashing tapes around the window, door, meterbox and other penetrations must be lapped over the lining board 3 by,ideally, at least 50 mm.

An appropriate apron flashing arrangement is shown in FIG. 12. In thisconfiguration, a flashing tape 19 is applied to the apron upstand 23 ofthe apron flashing 24 over the lining board 3.

Similarly, junctions between ballustrades and walls need to beappropriately flashed and an example of how this can be achieved isshown in FIG. 13. In the illustrated example, flexible flashing tape 19is dressed up and adhered to the lining board 3 behind the battens 26.

In most installations, the lining boards will be required to extendbelow the bottom plate 28 by around 15 mm minimum to form a drip edge.In certain applications, it is recommended that the lining boardmaintain a 100 mm minimum clearance between the bottom edge of the boardand finished ground as shown in FIGS. 14 and 15. It is also recommendedthat when the bottom edge of the panel 3 is cut on site to suit the siterequirements, the cut edge should be sealed with an appropriate primeror sealer. Naturally, the adjacent finished ground site must slope awayfrom the building in accordance with the relevant building coderequirements. It is important that the lining board is not installed insuch a way that it may remain with contact with standing water. Instructures where the lining boards 3 are being installed as bracing, allboard edges must be supported by the underlying framing. The particularinstallation requirements will depend on relevant local building codesand the particular form of lining boards. In preferred forms, the liningboard, the outer face will be marked to indicate appropriate fixingcentres.

While the examples discussed above all relate to timber framed wallstructures, it will be appreciated that the inventive concepts can alsobe applied to steel frame structures with appropriate adaptations withlining board fasteners and spacings as may be required.

Once the lining boards have been installed as discussed above, thebuilder has the option of sealing the roof or applying a roof coveringand taking required further steps necessary to achieve “lock up” withoutneeding to start on the outer brick veneer or cladding skin. Thisenables early commencement of the internal fit out which leads to theadvantages discussed above. The external skin, be it brick or claddingetc, can then be erected in the usual manner and in accordance with sitespecific conditions.

The numerous advantages of the preferred fibre cement lining board arediscussed in detail above, but can be summarised as being costeffective, light and easy to handle, multi-purpose (air barrier,bracing, moisture control, structured sub-wall etc), easy to cut and fixand easily identified by the selected colour which is distinctive in thelocal market.

Similarly, the advantages of the new method of dual skin framed wallconstruction, whether using the preferred lining board or analternative, are clear and represent a very significant move forwardover local prior art construction methods.

While the invention has been described with reference to specificexamples, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms.

1. An outer frame lining board for use as a lining board for an outerframe structure comprising a fibre cement sheet having a thickness ofmore than 3 mm but less than 4 mm, and at least two major faces, thefibre cement which sheet is pre-sealed on at least one major face priorto installation.
 2. An outer frame lining board according to claim 1wherein the fibre cement sheet has a thickness of around 3.5 mm.
 3. Anouter frame lining board according to claim 1 wherein a surface of theouter frame lining board includes markings to assist with alignment offasteners with standard stud spacings and the like and/or to facilitateeasy and accurate cutting and sizing of the sheets.
 4. An outer framelining board according to claim 3 wherein the markings are integrallyformed.
 5. An outer frame lining board according to claim 1 wherein theboard is distinguished at least in part by use of a coloured coating. 6.A method of construction of a framed dual skin wall structurecomprising: erecting an internal structural wall frame in situ; applyinga plurality of fibre cement lining boards which are pre-sealed on atleast one major face prior to installation to fully cover and seal theoutside of the wall frame excluding window and door openings and otherdesigned penetrations to form a first inner wall skin, applying a sealedroof or roof cover; and closing off the designed penetrations to achievea sufficiently sealed building envelope to achieve “lock up” prior tosubsequently constructing a second outer wall skin in the form of anexternal block wall or external cladding.
 7. A method of construction ofa framed wall structure according to claim 6 wherein the wall structureis a brick or block style masonry veneer structure.
 8. A method ofconstruction of a framed wall structure according to claim 6 wherein thewall structure includes a second outer wall skin in the form ofpanellised or plank style cladding.
 9. A method of construction of aframed wall structure according to any one of claim 6 using a facesealed fibre cement lining board with a thickness of more than 3 mm butless than 4 mm.
 10. (canceled)
 11. A framed dual skin wall structurecomprising: an internal structural wall frame; a plurality of fibrecement lining boards which are pre-sealed on at least one major faceprior to installation fully covering and sealing the outside of theinternal structural wall frame, excluding window and door openings andother designed penetrations, to form a first inner wall skin, a sealedroof or roof cover over the internal structural wall frame; and theinternal structural wall frame, first inner wall skin and sealed roof orroof cover being closed off at designed penetrations to achieve asufficiently sealed building envelope; and a second outer wall skinaround the internal structural wall frame and first inner wall skin, thebeing in the form of an external block wall or external cladding.
 12. Aframed dual skin wall structure according to claim 10 where at leastfibre cement lining board has a thickness of more than 3 mm but lessthan 4 mm.